This invention relates generally to electronic devices, and more particularly, to multimode audio amplifier circuitry for wireless electronic devices.
Electronic devices such as handheld electronic devices and other portable electronic devices are becoming increasingly popular. Examples of handheld devices include handheld computers, cellular telephones, media players, and hybrid devices that include the functionality of multiple devices of this type. Popular portable electronic devices that are somewhat larger than traditional handheld electronic devices include laptop computers and tablet computers.
Due in part to their mobile nature, portable electronic devices are often provided with wireless communications capabilities. For example, handheld electronic devices may use long-range wireless communications to communicate with wireless base stations. Cellular telephones and other devices with cellular capabilities may communicate using cellular telephone bands at 850 MHz, 900 MHz, 1800 MHz, 1900 MHz, and 2100 MHz. Portable electronic devices may also use short-range wireless communications links. For example, portable electronic devices may communicate using the Wi-Fi® (IEEE 802.11) bands at 2.4 GHz and 5.0 GHz and the Bluetooth® band at 2.4 GHz. Global positioning system signals at 1575 MHz may also be received by cellular telephones.
Portable electronic devices may also include audio amplifier circuitry for playing audio to a user. The audio amplifier circuitry may, for example, be used to play media files such as song files to a user through a headset.
Challenges arise when providing handheld devices with wireless capabilities and high quality audio amplifier circuitry. Some audio amplifiers exhibit good power consumption performance, but tend to be electrically noisy. Particularly when a user is performing a sensitive wireless operation such as when the user is receiving radio-frequency signals, the noise produced by the audio amplifier circuitry can interfere with proper operation of the device. Although less noisy audio amplifier circuitry could be used, low noise audio amplifier circuits tend to consume larger amounts of power, reducing battery life.
It would therefore be advantageous to be able to provide electronic devices that produce high quality audio signals without interfering with wireless operations or consuming excessive amounts of power.